Backpack



FIG. 1 is a perspective view of a backpack showing my new design;

FIG. 2 is a front view of the backpack as shown in FIG. 1;

FIG. 3 is a rear view of the backpack as shown in FIG. 1;

FIG. 4 is a right side view of the backpack as shown in FIG. 1;

FIG. 5 is a left side view of the backpack as shown in FIG. 1;

FIG. 6 is a top view of the backpack as shown in FIG. 1; and,

FIG. 7 is a bottom view of the backpack as shown in FIG. 1.

Any broken line illustration of environmental structure in the drawings and selected other features that may be shown as attached to the claimed design is for illustrative purposes only and forms no part of the claimed design. 

The ornamental design for a backpack, as shown and described. 